The present invention relates to an image forming apparatus using a consumable supply such as a photosensitive drum, toner, and the like.
In a conventional image forming apparatus, when a photosensitive drum as a consumable supply is exchanged, a fuse attached to the photosensitive drum is checked. When the fuse is not broken, it is considered that the photosensitive drum is a brand new one and not used yet. Accordingly, an accumulation print number counter is initialized, and the fuse is broken. After the time on, a print number is counted, so that a life of the photosensitive drum is measured.
Further, another conventional image forming apparatus is provided with a sensor for detecting whether a photosensitive drum is exchanged (refer to Patent Reference).
Patent Reference: Japanese Patent Publication No. 08-305225
In some cases, the conventional image forming apparatus may have four photosensitive drums for developing images in four colors as the consumable supplies. In this case, when one of the photosensitive drums is exchanged after the life thereof is expired, and an operator mistakenly exchanges another of the photosensitive drums whose life is not expired yet with a new photosensitive drum, the fuse of the new photosensitive drum is inevitably broken. Further, the accumulation print number counter of the conventional image forming apparatus is initialized.
Accordingly, even though the operator notices later that the photosensitive drum whose life is not expired yet is mistakenly exchanged with the new photosensitive drum, and the operator switches the new photosensitive drum back to the previously installed photosensitive drum, it is not possible to count an exact accumulation print number since the accumulation print number counter has been already initialized. Accordingly, it is difficult to accurately measure the life of the photosensitive drum.
Further, after the new photosensitive drum is switched back to the previously installed photosensitive drum, when the new photosensitive drum is installed in the conventional image forming apparatus one more time, the fuse of the new photosensitive drum is already broken. Accordingly, the accumulation print number counter is not initialized this time. As a result, it is not possible to count an exact accumulation print number of the new photosensitive drum. Further, even though the new photosensitive drum is installed, a message is displayed on a display unit to prompt the user to exchange the photosensitive drum.
In view of the problems described above, an object of the present invention is to provide an image forming apparatus capable of solving the problems of the conventional image forming apparatus, and preventing a new consumable supply from being exchanged even when a life thereof is not expired.
Further objects and advantages of the invention will be apparent from the following description of the invention.